Graphene is a unique material for the implementation of terahertz antennas due to extraordinary properties of the resulting devices, such as tunability and compactness. Existing graphene antennas are based on pure plasmonic structures, which are compact but show moderate to high losses. To achieve higher efficiency with low cost, one can apply the theory behind dielectric resonator antennas widely used in millimeter-wave systems. This paper presents the concept of hybridization of surface plasmon and dielectric wave modes. Then, via an analysis of one-dimensional structures, a comparison of the potential capabilities of pure and hybrid plasmonic antennas is performed from the perspectives of radiation efficiency, tunability, and miniaturization. Additionally, the impact of the quality of graphene upon the performance of the compared structures is evaluated. On the one hand, results show that hybrid structures deliver high gain with moderate miniaturization and tunability, rendering them suitable for applications requiring a delicate balance between the three aspects. On the other hand, pure plasmonic structures can provide higher miniaturization and tunability, yet with low efficiency, suggesting their use for application domains with high flexibility requirements or stringent physical constraints.

This paper presents a steady-state analysis of the isolated class-E2 converter outside nominal operation. By transforming the isolated class-E2 converter into the typical topology of the class-E inverter, the switching patterns can be comprehended on the parameter spaces easily. The output power and the power-conversion efficiency can be expressed as functions of circuit parameters such as coupling coefficient of the transformer, load resistance, and operating frequency. The class-E2 wireless power transfer (WPT) system was designed and implemented in this paper for verifying the analytical expressions. The analytical predictions of system performance against coupling-coefficient and load-resistance variations agreed with PSpice simulation and experimental results quantitatively, which showed the validity of the analytical expressions. Comparisons between the class-E2 and classD-E WPT systems are shown along with their discussions. Additionally, two application examples of the analytical expressions are introduced in this paper, which shows the usefulness of the analytical equations.

This article introduces 3 Cat-1, the first project of the Technical University of Catalonia to build and launch a nano-satellite. Its main scope is to develop, construct, assemble, test and launch into a low Earth orbit a CubeSat with seven different payloads (mono-atomic oxygen detector, graphene field-effect transistor, self-powered beacon, Geiger radiation counter, wireless power transfer (WPT), new topology solar cells and WPT experiment), all fitted in a single-unit CubeSat. On one hand, this is mainly an educational project in which the development of some of the subsystems is carried out by undergraduate and postgraduate students. The satellite demonstrates its capabilities as a cost-effective platform to perform small scientific experiments and to demonstrate some of the new technologies that it incorporates.

This paper deals with a comprehensive study and comparison on the conventional linear-assisted converter and a new structure named, LDO-assisted converter based on a new class-AB LDO regulator instead of the conventional linear one, in terms of efficiency, output ripple, and load transient response. The new structure reduces difference between input and output voltages and also switching frequency of the buck converter,
corresponding to higher power efficiency, desired for power management systems of battery operated devices like biomedical implants and energy harvesting applications. A comparison analysis is done and the results are validated in HSPICE in a 0.18 µm CMOS process.

Wireless RF power transfer requires the deployment of multiple energy transmitters (ETs) to cover an entire area of interest. This letter aims at bounding the minimum cumulative power that ETs need to inject into the network, such that the recipient nodes harvest sufficient power to operate. The main findings are that, in the worst case, this scales as O(s1-a/2), where s and a are the number of ETs and the channel path loss. That is, the overall power decreases with the number of ETs. It is also shown that sophisticated design for power transmission can further improve the scalability by s-1.

New exact critical conditions for predicting subharmonic instability in switching regulators are approximated by simple design-oriented expressions valid under practical conditions. These simplified expressions contain the ripple and slope information of the feedback control signal. Depending on the converter topology, the controller used and values of parasitic parameters, either the slope or the ripple can be dominant in predicting instability. A discussion on the validity of this interpretation is illustrated through six different examples of switching regulators using the concept of the spectral radius and the relative degree of the system loop. Using this approach, the boundary between the desired stable region and the subharmonic instability can be easily obtained. The theoretical results are validated by means of numerical simulations.

The issue that you are holding represents a milestone for a new initiative called “Late Breaking News” (LBN). This is the inaugural Special Issue of IEEE Transaction on Circuits and Systems II (TCAS II), presenting the best work submitted to the LBN track of International Symposium on Circuits and Systems (ISCAS) 2016. The purpose of the LBN initiative is to recognize the quickly changing nature of innovation in circuits and systems. We believe that this poses a unique opportunity for the IEEE Circuits and Systems Society (CAS) to emerge as a forum in which innovations that cross boundaries and platforms from signal processing to architecture, and from theory to application, can all be evaluated holistically. With this in mind, we created the new effort of LBN to allow a small and elite set of the best and most timely new results in any given year to be presented at special sessions within ISCAS and then published in this special issue of TCAS II. We are delighted with the overwhelming response to the LBN call for papers. These papers were originally submitted as brief, one-page abstracts and a small subset were selected by a team of highly qualified reviewers and experts. The final selected papers were presented a few months later at ISCAS, giving audiences at ISCAS a chance to see very interesting work in a range of topics. For this year, the final sessions were organized around the following three themes: 1)
Emerging technologies and low-power subsystems;

Networks-on-Chip (NoCs) are currently the paradigm of choice to interconnect the cores of a chip multiprocessor. However, conventional NoCs may not suffice to fulfill the on-chip communication requirements of processors with hundreds or thousands of cores. The main reason is that the performance of such networks drops as the number of cores grows, especially in the presence of multicast and broadcast traffic. This not only limits the scalability of current multiprocessor architectures, but also sets a performance wall that prevents the development of architectures that generate moderate-to-high levels of multicast. In this paper, a Wireless Network-on-Chip (WNoC) where all cores share a single broadband channel is presented. Such design is conceived to provide low latency and ordered delivery for multicast/broadcast traffic, in an attempt to complement a wireline NoC that will transport the rest of communication flows. To assess the feasibility of this approach, the network performance of WNoC is analyzed as a function of the system size and the channel capacity, and then compared to that of wireline NoCs with embedded multicast support. Based on this evaluation, preliminary results on the potential performance of the proposed hybrid scheme are provided, together with guidelines for the design of MAC protocols for WNoC.

This paper presents the modeling of linear-assisted DC-DC regulators. This kind of voltage regulators consists of a switching converter together with a classic or LDO (low dropout) linear voltage regulator. While the linear regulator provides the constant output voltage, the switching converter conducts nearly all the current provided in the output load, and keeping the regulator current close to zero where the higher efficiency is achieved. However, the circuit could be unstable due to some critical parameters such as parasitic output capacitance; as a consequence, the mathematical modeling is obtained to study and corroborate the stability of the whole system.

In this paper, a new structure based on linear-assisted DC-DC buck converter principle is proposed. Using a segmented LDO regulator instead of the conventional linear one in the hybrid scheme, reduces the difference between input and output voltages and also the switching frequency of the buck converter, while the circuit provides a lower output ripple, better transient response. In addition, the proposal achieves higher power efficiency rather than the linear-assisted converter, desired for power management systems of battery operated devices like biomedical implants and energy harvesting applications. A comparison analysis is done with regards to the mentioned performance indexes between the proposed structure and linear-assisted buck converter and the results are validated in HSPICE in a 0.35 µm CMOS process.

This paper presents a tool developed to help engineers to design and develop sustainable projects. The tool has been designed to introduce and evaluate the sustainability of engineering projects in general, but here we show its application to assess the final project of an engineering degree. This tool is a guide for students to introduce and estimate the sustainability of their projects, but it also helps teachers to assess them. The tool is based on the Socratic Methodology and consists of a matrix where each cell contains several questions that students must consider during the project development and which they must answer in their project report. A positive or negative mark is assigned to every cell, and the sum of all marks states the project sustainability. However, the result is not as simplistic as a final
number, but a descriptive sustainability analysis where questions are answered and every mark justified. A pilot test with some students has obtained good results, but the first Final Degree Project using this methodology will be read in July 2016.

This paper extends a previous design of an energy management strategy based on Fuzzy Logic Control (FLC) for a residential grid-tied microgrid including a Hybrid Renewable Energy System (HRES) and an Energy Storage System (ESS). The main goal of the proposed design is to improve the grid power profile while satisfying the constraints established by the ESS. The strategy extension includes generation and demand forecasting in order to predict the future behavior of the microgrid. According to the forecast error and the battery State-of-Charge (SOC) the proposed strategy increases/decreases the grid power with the purpose of smoothing the power exchanged with the grid. The performance of the proposed strategy is verified through comparative numerical simulations using real data measured at the microgrid of the Public University of Navarre (UPNa).

Electrical energy generation systems based on renewable energy sources have been promoted in recent years. The introduction of these systems has changed the centralized energy model to become a distributed energy model. The variability, more or less predictable, in electrical energy production based on renewable energies is a particularity of some distributed power generation systems. These variations, due to the nature of the power source, are a further disadvantage when considering the variability in energy demand. The fluctuations between energy generated and energy demanded makes it necessary to increase the use of power electronic systems in order to manage energy by storing the excess of energy during times of low demand and injecting to the grid when higher demand requires it. Some electrical energy generation systems are not able to manage variable power flow, for this reason the efficiency and their influence on the grid must be considered when their operating regime is variable.
This thesis is framed within the field of electrical energy conversion in power generation systems based on renewable and non-manageable energy resources. This research scope focuses on the impact in terms of efficiency of power converters when their switches are based on transistors connected in parallel operating in case of variable power flow. Therefore, this thesis explores the energetic efficiency converters considering the influence in the current distortion by measuring the Total Harmonic Distortion (THD). To evaluate these parameters a switching strategy has been developed providing advanced configuration capabilities, selecting the number of transistors within the power switch according to the operating conditions of the power converter, applying switch multiplexed techniques and adaptive control strategies. Two main strategies are developed according to the switching frequency, maintaining a constant switching frequency in the power converter or maintaining a constant switching frequency in the transistors within the power switch. Both of them can decrease the number of switchings in each transistor.
A study of performance of transistors connected in parallel is presented, highlighting the factors involved in the transistor current sharing, examining the existing techniques and analyzing their influence in transistor losses. Loss estimation models are introduced to evaluate the effects of the adaptive switching techniques on two of the main devices of the power converter, the transistors and the grid coupled inductor.
The experimental results are obtained from a single-phase inverter with power switches based on four transistors connected in parallel. The test results show the power losses in different operating conditions, distinguishing the conduction losses, the switching losses and the losses due to the coupling inductor.

This paper presents the design exploration of a basic cascode circuit (CAS) targeted to increase the intrinsic gain A# of a graphene field-effect-transistor (GFET) by decreasing its output conductance go. First, the parameters of a large-signal compact-model, based on drift-diffusion carrier transport, are fit to measurements carried on 2 CVD
GFETs, fabricated independently by different research groups. Second, CAS circuits are simulated to perform a design exploration and provide design guidelines. Third, CAS circuits are fabricated and consequently measured. Performance metrics are provided in terms of go, transconductance gm and hence A#. Against these metrics, a
quantitative comparison between CAS and GFET is performed and conclusions are derived.

Given the high multi-disciplinarity of Molecular Communications (MolCom), researchers often face significant difficulties to understand each other. This impairment not only affect researchers with different backgrounds, but it also affects the different software tools. This paper motivates the development of the Molecular Communication Markup Language (MolComML). MolComML is proposed as an XML-based format to represent the considered elements, interactions, configuration and results of the experiments and simulations in the field of MolCom. MolComML is designed with the objective of converging all fields of research within Mol-Com to help the exchange of information. We overview its main functionality and define its basic composing elements.

This paper analyzes the influence of neighboring absorbing receivers in a point-to-point Diffusion-based Molecular communication (DMC) link, following a simulation-driven approach. It is shown that the distance from the transmitter-receiver link, the distance between receivers and their radius have a noticeable impact upon both amplitude and signal detection.

Graphene is a unique material for the implementation of terahertz antennas due to extraordinary properties of the resulting devices, such as tunability and compactness. Existing graphene antennas are based on pure plasmonic structures, which are compact but show moderate to high losses. To achieve higher efficiency with low cost, one can apply the theory behind dielectric resonator antennas widely used in millimeter-wave systems. This paper presents the concept of hybridization of surface plasmon and dielectric wave modes. Radiation efficiency, reconfigurability, and miniaturization of antennas built upon this principle are qualitatively discussed and compared with those of pure plasmonic antennas. To this end, a quantitative study of pure and hybrid plas-monic one-dimensional guided-wave structures is performed. The results show that hybrid structures can be employed to design terahertz antennas with high radiation efficiency and gain, moderate miniaturization, and tunability, while terahertz antennas based on pure plasmonic structures can provide high miniaturization and tunability yet with low radiation efficiency and gain.

Communications are becoming the bottleneck in the performance of Chip Multiprocessor (CMP). To address this issue, the use of wireless communications within a chip has been proposed, since they offer a low latency among nodes and high reconfigurability. The chip scenario has the particularity that is static, and the multipath can be known a priori. Within this context, we propose in this paper a simple yet very efficient modulation technique, based on Impulse Radio-On–Off-Keying (IR-OOK), which significantly optimizes the performance in Wireless Network-on-Chip (WNoC) as well as off-chip scenarios. This technique is based on interspersing information pulses among the reflected pulses in order to reduce the time between pulses, thus increasing the data rate. We prove that the final data rate can be considerably increased without increasing the hardware complexity of the transceiver.

Linear-assisted DC/DC converters (or linear-switching hybrid DC/DC converters) consist of a voltage linear regulator (classic NPN or nMOS topologies and LDO) connected in parallel with a switching DC/DC converter. They are a good candidate for energy processing in photovoltaic solar facilities. In order to control these hybrid structures, different strategies exist, allowing fixing the switching frequency as a function of some parameters of the linear regulator. This article compares two control strategies that, although can be applied to the same circuital structure of linear-assisted converter, are sensibly different. The first one, reported in previous literature, cancels completely the average current through the linear regulator in steady state to achieve a reduction of the losses. Thus the efficiency of the whole system increases and almost equals the one of the standalone switching converter. The proposed approach, in spite of a slightly increment of linear regulator’s losses, reduces the output ripple due to the crossover distortion of linear regulator output stage.

The Wireless Network-on-Chip (WNoC) paradigm holds considerable promise for the implementation of fast and efficient on-chip networks in manycore chips. Among other advantages, wireless communications provide natural broadcast support, a highly desirable feature in manycore architectures yet difficult to achieve with current interconnects. As technology advancements allow the integration of more wireless interfaces within the same chip, a critical aspect is how to efficiently share the wireless medium while reliably carrying broadcast traffic. This paper introduces the {Broadcast, Reliability, Sensing} protocol (BRS-MAC), which exploits the particularities of the WNoC context to meet its stringent requirements. BRS-MAC is flexible and employs a collision detection and notification scheme that scales with the number of receivers, making it compatible with broadcast communications. The proposed protocol is modeled and evaluated, showing a clear latency advantage with respect to wired on-chip networks and WNoCs with token passing.

Powering wireless sensors has become a key challenge to enable the Internet of Things vision. A common approach to achieve this is to use Energy Harvesting. By means of this technology, sensors have access to an unlimited source of energy, which can extend their operation lifetime.
Unfortunately, typically the energy that is available surrounding the sensors is neither controllable nor predictable, showing significant variations in the expected harvested energy in terms of both space and time. This can cause the temporal disconnection of parts of the wireless network.
The objective of this thesis is to mitigate the undesirable effects of the spatio-temporal variations of the surrounding energy, by following a two-fold approach: first, to provide a high level understanding of the involved trade-offs in the design of a wireless sensor and the interconnecting network. Then, to synthesize an energy field to guarantee the required amount of ambient energy at the surrounding of the considered nodes.
The first part of the thesis starts by presenting a formal description of the environment. The derived energy model is first used to answer fundamental questions on throughput scaling and, then, to provide design guidelines for energy harvesting sensors. It is found that energy harvesting is a scalable solution to power and recharge IoT sensors, which require additional circuit design to guarantee their operation in energy scarce scenarios.
On the second part of this work, wireless RF power transmission from controllable Energy Transmitters (ETs) is considered as a feasible approach to synthesize an energy field to power sensors at-a-distance, hence tackling the lack of available ambient energy in spatial regions, at the cost of occupying the available wireless spectrum. Due to the limited transmission range of this approach, the use of multiple ETs to cover entire areas is required. We first discuss on the feasibility of synthesizing energy fields with multiple ETs. We show that powering those sensors with multiple ETs stands as a scalable approach, which presents a trade-off between the channel conditions and the energy multiplexing design complexity. We, then, present an opportunistic scheme to leverage the generated interferences of multiple ETs. Finally, we propose a joint energy and communication method to circumvent the imposed trade-offs of in-band multi-ET wireless RF power transmission.
Overall, we find that the analysis and design of wireless networked sensing systems, enabled by energy harvesting, and the development of novel wireless RF power transmissions schemes will play a key role in the future development of autonomous IoT deployments.

This article presents the design of a 4.5-V, 450-mA low drop-out (LDO) voltage linear regulator based on a two-stage cascoded operational transconductance amplifier (OTA) as error amplifier. The aforementioned two-stage OTA is designed with cascoded current mirroring technique to boost up the output impedance. The proposed OTA has a DC gain of 101 dB under no load condition. The designed reference voltage included in the LDO regulator is provided by a band gap reference with the temperature coefficient (T¿) of 0.025 mV/ºC. The proposed LDO regulator has a maximum drop-out voltage of 0.5 V @ 450 mA of load current, and has the worst case power supply rejection ratio (PSRR) of [54.5 dB, 34.3 dB] @ [100 Hz, 10 kHz] in full load condition. All the proposed circuits are designed using a 0.35 µm CMOS technology. The design is checked in order to corroborate its performance for wide range of input voltage, founding that the circuit design works fine meeting all the initial specification requirements.

This paper presents an output-capacitorless low dropout (LDO) regulator based on improved flipped voltage follower power stage for use in power management circuits. A new error amplifier (EA) structure, named as gain-bandwidth enhanced EA, is embedded in the LDO regulator. The LDO regulator is designed for the input and output voltages of 1.2 V and 1 V, respectively. Fast transients, low overshoot and undershoot, and low quiescent current of 6 µA are achieved for the proposed circuit. The LDO regulator is designed for maximum load current of 50 mA, achieving the current and power efficiencies of 99.99% and 83.3%, respectively. Additionally, up to 131 pF capacitance is used in the proposed LDO structure. The proposed circuit is designed and verified in HSPICE in TSMC 0.18 µm mixed signal CMOS process.

In this paper, a new structure based on linear-assisted DC-DC buck converter principle is proposed. Using a new class-AB LDO regulator instead of the conventional linear one (based on a push-pull output stage) in the hybrid scheme, reduces the difference between input and output voltages and also the switching frequency of the buck converter. Thus, the proposal achieves higher power efficiency rather than the conventional linear-assisted converter, desired for power management systems of battery operated devices like biomedical implants and energy harvesting applications. In addition, the circuit provides a lower output ripple and better transient response. A comparison analysis is done with regards to the considered performance indexes between the proposed structure and linear-assisted buck converter, and the results are validated in HSPICE in a 0.35 µm CMOS process.

Recent years have seen the emergence and ubiquitous adoption of Chip Multiprocessors (CMPs), which rely on the coordinated operation of multiple execution units or cores. Successive CMP generations integrate a larger number of cores seeking higher performance with a reasonable cost envelope. For this trend to continue, however, important scalability issues need to be solved at different levels of design. Scaling the interconnect fabric is a grand challenge by itself, as new Network-on-Chip (NoC) proposals need to overcome the performance hurdles found when dealing with the increasingly variable and heterogeneous communication demands of manycore processors. Fast and flexible NoC solutions are needed to prevent communication become a performance bottleneck, situation that would severely limit the design space at the architectural level and eventually lead to the use of software frameworks that are slow, inefficient, or less programmable.
The emergence of novel interconnect technologies has opened the door to a plethora of new NoCs promising greater scalability and architectural flexibility. In particular, wireless on-chip communication has garnered considerable attention due to its inherent broadcast capabilities, low latency, and system-level simplicity. Most of the resulting Wireless Network-on-Chip (WNoC) proposals have set the focus on leveraging the latency advantage of this paradigm by creating multiple wireless channels to interconnect far-apart cores. This strategy is effective as the complement of wired NoCs at moderate scales, but is likely to be overshadowed at larger scales by technologies such as nanophotonics unless bandwidth is unrealistically improved.
This dissertation presents the concept of Broadcast-Oriented Wireless Network-on-Chip (BoWNoC), a new approach that attempts to foster the inherent simplicity, flexibility, and broadcast capabilities of the wireless technology by integrating one on-chip antenna and transceiver per processor core. This paradigm is part of a broader hybrid vision where the BoWNoC serves latency-critical and broadcast traffic, tightly coupled to a wired plane oriented to large flows of data. By virtue of its scalable broadcast support, BoWNoC may become the key enabler of a wealth of unconventional hardware architectures and algorithmic approaches, eventually leading to a significant improvement of the performance, energy efficiency, scalability and programmability of manycore chips.
The present work aims not only to lay the fundamentals of the BoWNoC paradigm, but also to demonstrate its viability from the electronic implementation, network design, and multiprocessor architecture perspectives. An exploration at the physical level of design validates the feasibility of the approach at millimeter-wave bands in the short term, and then suggests the use of graphene-based antennas in the terahertz band in the long term. At the link level, this thesis provides an insightful context analysis that is used, afterwards, to drive the design of a lightweight protocol that reliably serves broadcast traffic with substantial latency improvements over state-of-the-art NoCs. At the network level, our hybrid vision is evaluated putting emphasis on the flexibility provided at the network interface level, showing outstanding speedups for a wide set of traffic patterns. At the architecture level, the potential impact of the BoWNoC paradigm on the design of manycore chips is not only qualitatively discussed in general, but also quantitatively assessed in a particular architecture for fast synchronization. Results demonstrate that the impact of BoWNoC can go beyond simply improving the network performance, thereby representing a possible game changer in the manycore era.

The Bologna Process is a voluntary intergovernmental European cooperation initiative that led to the creation of the named European Higher Education Area (EHEA). EHEA was formed to promote mobility, increase academic recognition and attract students and staff from around the world to Europe. In this framework, since 2009, the Barcelona College of Industrial Engineering (Escuela Universitaria de Ingeniería Técnica Industrial de Barcelona – EUETIB) of the Technical University of Catalonia – BarcelonaTech (UPC) is offering the 4-year Bachelor Degree in Energy Engineering since 2009 with a total number of ECTS credits of 240. Current article deals with the inclusion of the sizing and design of solar energy systems in the context of this degree. In particular, and although this topic was eventually abandoned in the initial degree curriculum, the paper deals with the development of a 3rd-year course, Energy Integration, that focuses on this topic.

This article aims to present the design of a 4.5-V, 450-mA low drop-out (LDO) voltage linear regulator based on a twostage cascoded operational transconductance amplifier (OTA) as error amplifier. The aforementioned two-stage OTA is designed with cascoded current mirroring technique to boost up the output impedance. The proposed OTA has a DC gain of 101 dB under no load condition. The designed reference voltage included in the LDO regulator is provided by a band gap reference with the temperature coefficient (T¿) of 0.025 mV/ºC. The proposed LDO regulator has a maximum drop-out voltage of 0.5 V @ 450 mA of load current, and has the worst case power supply rejection ratio (PSRR) of [54.5 dB, 34.3 dB] @ [100 Hz, 10 kHz] in full load condition. All the proposed circuits are designed using a 0.35 µm CMOS technology. The design is checked in order to corroborate its performance for wide range of input voltage, founding that the circuit design works fine meeting all the initial specification requirements.

This article presents a low quiescent current output capacitorless quasi-digital CMOS LDO regulator with controlled pass transistors according to load demands. The pass transistor of the LDO is broken up to two smaller sizes based on a breakup criterion defined here, which considers the maximum output voltage variations to different load current steps to find the suitable current boundary for breaking up. This criterion shows that low load conditions will cause more output variations and settling time if the pass transistor is used in its maximum size. Therefore, using one smaller transistor for low load currents, and another one larger for higher currents, is the best trade-off between output variations, complexity, and power dissipation. The proposed LDO regulator has been designed and post-simulated in HSPICE in a 0.35 µm CMOS process to supply a load current between 0-100 mA while consumes 7.6 µA quiescent current. The results reveal 46% and 69% improvement on the output voltage variations and settling time, respectively.

A purification water plant is a hydraulic system that needs an automation control to achieve an effective and sustainable management taking into account the water resource preservation. The World Health Organisation Drinking Water Guidelines (WHO, 1993) provides an appropriate context for the subject matter covered: “Disinfection is unquestionably the most important step in the treatment of water for public supply. The destruction of microbiologic al pathogens is essential and almost invariably involves the use of reactive agents such as chlorine, which are not only powerful biocides but also capable of reacting with other water constituents to form new compounds with potentially long-term health effects”. Chlorine dosing is one of the essential treatment processes in purification water plant because chlorine has been the most commonly used disinfectant for the last hundred years. Chlorine reacts with natural organic matter in water to form DBP’s (disinfection by products), and researchers are becoming increasingly concerned about the health problems those products can cause. This fact highlights the sensitivity of the chlorination process, and the importance of having a reliable accurate control system to ensure that the amount of chlorine dosed in drinking water is correct.
For this reason, in this paper a novel automated chlorination process is proposed. This process has three main features: variable dynamics (the behaviour of the plant is nonlinear and with unlumped parameters) and variable large delay (because there is a delay between the input chlorine concentration and the output chlorine concentration due to the contaminant transport), and sudden and undesired appearance of ammonium in the treated water due to chlorination. The variation of the plant parameters (dynamic and delay) in the plant operation range is caused by the variation of inflow chlorine. These features lead to the development of parameter time variable control model and to the design of a parameter time variable controller. The global control model is built from the combination of the identified local models (in each operating point, a fraction of the operation range of the plant) by classical identification tehniques. A variable Smith Predictor scheme is used with the goal to cancel the large variable delay. The control scheme is based on a feedback using a PI (Proportional-Integral) switched according to inflow concentration variability. On the other hand to counteract the ammonium effect appearance a feedforward configuration is used. The establishment of this new control methodology has represented a significant change in the operation of the plant providing a better water quality and chlorine saving. This methodology has been applied at the purification water plant in Sant Joan Despí (Barcelona, Spain)

This paper presents a guide to help engineers to design and develop sustainable projects. The guide is the culmination of previous studies published over the last seven years in JENUI. The guide has been designed to introduce and evaluate the sustainability of engineering projects in general, but here we pre-sent how it can be applied to the final project of an engineering degree. This tool is a guide for students. to introduce and estimate the sustainability of their projects, but it also helps teachers to assess them. The guide is based on the Socratic Methodology and consists of a matrix where each cell contains several questions that students must consider during the project development and which they must answer in their project report. A positive or negative mark is assigned to every cell, and the sum of all marks states the project sustainability. However, the result is not as simplistic as a final number, but a descriptive sustainability analysis where all questions are answered and every mark justified.
A pilot test with some students has obtained good results, but the first Final Degree Project using the proposed methodology will be read in July 2016.

Several countries of the Mediterranean Area face the increase in the energy price and the weakness of the electrical grid (limited increase in power, interruptions, etc.), which undermines security of supply in critical facilities like hospitals, schools, etc. and creates financial burdens on businesses. These electricity supply problems are common to Lebanon and Palestine because of scarce quality and regular interruptions and cuts-off. During those periods that the utility grid is absent, electricity is supplied by diesel generators (gensets). As an alternative to using, exclusively, diesel fuel generators as back-up, PV hybrid power plants, with or without storage, have been demonstrated to be a cost effective solution whilst reducing pollution and energy dependency. The paper highlights the methodology, solution and lessons learned in Lebanon and Palestine during the development of two Projects funded by the European Union (EU): “MED-Solar [www.medsolarproject.com]” and “CEDRO IV [www.cedro-undp.org]” for the integration of PV to industrial consumers with multiple grid supply and energy management. Within the framework of the projects, 12 adapted PV hybrid demonstration plants have been constructed in Lebanon (9), Palestine (2) and Jordan (1) and are presented in the present paper.

The environmental and economic benefits related to the reduction of both carbon dioxide emission and transmission losses have made distributed renewable generation systems became a competitive solution for future power systems. In this context, Microgrids (MG) are considered as the key building blocks of smart grids and have aroused great attention in the last decade for their potential and the impact they may have in the coming future. The MG concept has captured great attention in the last years since it can be considered one of the most suitable alternatives for integration of distributed generation units in the utility grid. However, this integration involves some challenges to deal with especially when penetration of Renewable Energy Sources (RES) into the distribution network is increased. Therefore, an effective Energy Management System (EMS) is required to ensure optimal energy utilization within the MG, consequently, facilitating both the grid integration and operator control. In this regard, the EMS strategy design depends on the application, MG power architecture, and the power management capability of the MG elements. This dissertation research focuses on the design of different EMS strategies based on Fuzzy Logic Control (FLC) for a residential grid-connected electro-thermal MG including renewable power generation (i.e. photovoltaic and wind turbine generators) and storage capability (i.e. battery bank and water storage tank). The main goal of the FLC-based EMS strategies is to minimize the grid power fluctuations while keeping the battery State-of-Charge (SOC) within secure limits. In order to accomplish this goal, the controller design parameters, such as membership functions and rule-base, of the FLC-based EMS strategies, are adjusted to optimize a pre-defined set of quality criteria of the MG behavior. The analysis and design of the FLC-based EMS strategies for electrical and electro-thermal MG power architectures are developed considering two different scenarios. A first scenario where the MG power forecasting is not provided and a second scenario where the forecast of generation power and load demand are considered. A comparison with the different EMS strategies is presented in simulation level, whereas the features of the enhanced FLC-based EMS strategies are experimentally tested on a real residential microgrid implemented at the Public University of Navarre (UPNa)

Linear-switching hybrid DC/DC converters consist of a voltage linear regulator (classic NPN or nMOS topologies and LDO) connected in parallel with a switching DC/DC converter. In order to control these hybrid structures, different strategies exist, allowing to fix the switching frequency as a function of some parameters of the linear regulator. This article compares two control strategies that, although can be applied to the same circuital structure of linear-assisted converter, are sensibly different. The first one, reported in previous literature, cancels completely the average current through the linear regulator in steady state to achieve a reduction of the losses. Thus the efficiency of the whole system increases and almost equals the one of the standalone switching converter. The proposed approach, in spite of a slightly increment of linear regulator’s losses, reduces the output ripple due to the crossover distortion of linear regulator output stage.

The Bologna Process is a voluntary intergovernmental European cooperation initiative that led to the creation of the named European Higher Education Area (EHEA). EHEA was formed to promote mobility, increase academic recognition and attract students and staff from around the world to Europe. In this framework, since 2009, the Barcelona College of Industrial Engineering (Escuela Universitaria de Ingeniería Técnica Industrial de Barcelona – EUETIB) of the Technical University of Catalonia – BarcelonaTech (UPC) is offering the 4-year Bachelor Degree in Energy Engineering since 2009 with a total number of ECTS credits of 240. Current article deals with the inclusion of the sizing and design of solar energy systems in the context of this degree. In particular, and although this topic was eventually abandoned in the initial degree curriculum, the paper deals with the development of a 3rd-year course, Energy Integration, that focuses on this topic.

Simultaneous Wireless Information and Power Transmission (SWIPT) has been proposed as a feasible solution to enable joint power and data transfer for the nodes of a battery-less wireless networked sensor system. Different from existing approaches, where the incident energy is split between decoding and harvesting blocks at the receiver chain, this paper describes the design and implementation of an all-digital receiver circuit. We leverage the internal control signals of the circuit, targeting ultra-low power consumption, low bit-rate applications in SWIPT. A proof-of-concept receiver is modeled, implemented using off-the-shelf hardware, and validated through extensive experiments. Quantitative results demonstrate the benefits of this joint energy-data reception approach through a single receiver chain, offering bit-rates of 400 bps.

This paper deals with a circuit proposal along with theoretical analysis to provide a solution for enhancing
the stability and transient performance of external capacitorless low-dropout regulators (CL-LDOs) by segmenting the
pass transistor to smaller sizes. The stability and transient analysis is carried out on the CL-LDO with two different
size-segmented pass transistors in comparison with the conventional CL-LDO with single large size pass device. The
analysis shows that the pass transistor segmentation leads to better stability, i.e., greater phase margin especially at
no-load and light-load conditions, wider bandwidth, and improved transient behavior, i.e., lower settling time and output
voltage deviations due to the load transients. The aforementioned topologies are modeled and validated in HSPICE
using a 0.35 µm CMOS process, and the results are in conformity with the analytical statements.

This paper introduces the concept of switch-mode tunable emulated reactive networks. The idea of implementing reactive networks based on the theory of gyrators is proposed and characterized in an application-driven design-oriented context. By means of using switch-mode power processing converters to synthesize gyrators, small
capacitors or inductors are effectively multiplied to emulate larger ideally lossless reactive elements. The proposed idea enables to electronically tune the values of reactive elements by means of timing control variables. The proposed tunable reactive networks target many potential applications such as tunable-front-ends for energy harvesting, electronic compensating active power filters, and tunable-front-ends for wireless power transfer links.

This paper proposes the use of double-frequency (DF) buck converter architecture consisting of a merged structure of high and low frequency buck cells as a candidate topology for envelope elimination and restoration (EER) applications and integrated power supply of RF power amplifiers (RFPA) to obtain favorable tradeoffs in terms of efficiency, switching ripple, bandwidth, and tracking capability. It is shown that having two degrees of freedom in designing the DF buck helps to achieve high efficiency, low output ripples, and tracking capability with low ripples, simultaneously. A comparison analysis is done with regards to the mentioned performance indexes with the standard and three-level buck converters; in addition, the results are validated in HSPICE in BSIM3V3 0.35-µm CMOS process.

We appreciate the careful analysis and comments by Frégonèse and Zimmer, where they show that the model proposed, accurately reproduces experimental data from graphene FETs (GFETs) when an appropriate smoothing factor is used. The authors have proposed an extension of this model by Frégonèse et al. with an exact calculation of a denominator. We compared the model extension with the original work. Unfortunately, we did not use a suitable smoothing factor in our comparison, which lead to a strong artifact in the calculations and was absent in the exact solution. Following the argument, the authors agree with our colleagues that there is no artifact at the Dirac point in their GFET compact-model when a proper smoothing factor is used. We were not aware of the requirement of such a factor in specific cases when implementing the model because it is not mentioned; therefore, we apologize for misrepresenting their work.

This Mixed Signal Letter presents a proposal of four-quadrant linear-assisted DC/DC voltage regulator. In this topology, a class-AB linear voltage amplifier assists a four-quadrant switching DC/DC converter in order to obtain a compact circuit with advantages of both alternatives; i.e., high efficiency, inherent in switching converters, and low output ripple and fast reaction to the load changes that are characteristics of linear regulators. In order to reduce the power dissipation in the linear regulator, it is considered as an assisting circuit for providing just a small fraction of the total load current. Furthermore, this stage provides the required clock signal for the switching counterpart, obtaining a compact topology thanks to the reduction of the complexity in the design of the control scheme for the switching converter. In fact, the proposed topology can be addressed to on-chip practical implementations, since no output capacitors are required. This last advantage provides the possibility of obtaining good-performance power-supply modulators for envelope tracking techniques in power amplifiers. The implementation and results indicate that the proposed four-quadrant linear-assisted DC/DC regulator can achieve a notably compacting and higher performance, while consuming less power in comparison to linear alternatives.

This paper presents the design of a low complexity Fuzzy Logic Controller of only 25-rules to be embedded in an Energy Management System for a residential grid-connected microgrid including Renewable Energy Sources and storage capability. The system assumes that neither the renewable generation nor the load demand is controllable. The main goal of the design is to minimize the grid power profile fluctuations while keeping the Battery State of Charge within secure limits. Instead of using forecasting-based methods, the proposed approach uses both the microgrid energy rate-of-change and the battery SOC to increase, decrease or maintain the power delivered/absorbed by the mains. The controller design parameters (membership functions and rule-base) are adjusted to optimize a pre-defined set of quality criteria of the microgrid behavior. A comparison with other proposals seeking the same goal is presented at simulation level, whereas the features of the proposed design are experimentally tested on a real residential microgrid implemented at the Public University of Navarre.

Wireless RF power transmission from dedicated Energy Transmitters (ETs) is emerging as a promising approach to enable battery-less wireless networked sensor systems. However, when data communication and RF energy recharging occur in-band, sharing the RF medium and devoting separate access times for both operations
raises architectural and protocol level challenges. This paper proposes a novel method of concurrent transmission of data and energy to solve this problem, allowing ETs to transmit energy and sensors to transmit data in the same band synchronously. Our key idea concerns devising a physical layer modulation scheme that allows the data transmitting
node to introduce variations in the envelope of the energy signal at the intended recipient. We implemented a proofof-concept receiver, modeled and validated through extensive experimentation. We then propose a new physical layer mechanism for guaranteed successful delivery of information in a point-to-point link. Quantitative results demonstrate the feasibility of joint energy-data transfer, along with its associated benefits and tradeoffs.